Manual Setup

To set up networking the key file is /etc/network/interfaces.
Examples of what to add to this file are included below, illustrating
both DHCP for automatically obtaining network information from a
server, and a manual setup.

When changes are made to the network manually, (e.g., by editing
/etc/network/interfaces), restart the network with:

# wajig restart networking

Note that to have networking started in this way you need to have
auto eth0 in /etc/network/interfaces. Otherwise the
start-up script /etc/init.d/networking will not start
eth0. The start-up script calls ifup -a which only
starts those interfaces marked as auto. You can still
manually start the network with ifup eth0.